kernel/drivers/gpu/drm/bridge/ptn3460.c

   1 /*
   2  * NXP PTN3460 DP/LVDS bridge driver
   3  *
   4  * Copyright (C) 2013 Google, Inc.
   5  *
   6  * This software is licensed under the terms of the GNU General Public
   7  * License version 2, as published by the Free Software Foundation, and
   8  * may be copied, distributed, and modified under those terms.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/delay.h>
  17 #include <linux/gpio.h>
  18 #include <linux/i2c.h>
  19 #include <linux/module.h>
  20 #include <linux/of.h>
  21 #include <linux/of_gpio.h>
  22 #include <linux/of_graph.h>
  23
  24 #include <drm/drm_panel.h>
  25
  26 #include "bridge/ptn3460.h"
  27
  28 #include "drm_crtc.h"
  29 #include "drm_crtc_helper.h"
  30 #include "drm_edid.h"
  31 #include "drmP.h"
  32
  33 #define PTN3460_EDID_ADDR                       0x0
  34 #define PTN3460_EDID_EMULATION_ADDR             0x84
  35 #define PTN3460_EDID_ENABLE_EMULATION           0
  36 #define PTN3460_EDID_EMULATION_SELECTION        1
  37 #define PTN3460_EDID_SRAM_LOAD_ADDR             0x85
  38
  39 struct ptn3460_bridge {
  40         struct drm_connector connector;
  41         struct i2c_client *client;
  42         struct drm_bridge bridge;
  43         struct edid *edid;
  44         struct drm_panel *panel;
  45         struct gpio_desc *gpio_pd_n;
  46         struct gpio_desc *gpio_rst_n;
  47         u32 edid_emulation;
  48         bool enabled;
  49 };
  50
  51 static inline struct ptn3460_bridge *
  52                 bridge_to_ptn3460(struct drm_bridge *bridge)
  53 {
  54         return container_of(bridge, struct ptn3460_bridge, bridge);
  55 }
  56
  57 static inline struct ptn3460_bridge *
  58                 connector_to_ptn3460(struct drm_connector *connector)
  59 {
  60         return container_of(connector, struct ptn3460_bridge, connector);
  61 }
  62
  63 static int ptn3460_read_bytes(struct ptn3460_bridge *ptn_bridge, char addr,
  64                 u8 *buf, int len)
  65 {
  66         int ret;
  67
  68         ret = i2c_master_send(ptn_bridge->client, &addr, 1);
  69         if (ret <= 0) {
  70                 DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
  71                 return ret;
  72         }
  73
  74         ret = i2c_master_recv(ptn_bridge->client, buf, len);
  75         if (ret <= 0) {
  76                 DRM_ERROR("Failed to recv i2c data, ret=%d\n", ret);
  77                 return ret;
  78         }
  79
  80         return 0;
  81 }
  82
  83 static int ptn3460_write_byte(struct ptn3460_bridge *ptn_bridge, char addr,
  84                 char val)
  85 {
  86         int ret;
  87         char buf[2];
  88
  89         buf[0] = addr;
  90         buf[1] = val;
  91
  92         ret = i2c_master_send(ptn_bridge->client, buf, ARRAY_SIZE(buf));
  93         if (ret <= 0) {
  94                 DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
  95                 return ret;
  96         }
  97
  98         return 0;
  99 }
 100
 101 static int ptn3460_select_edid(struct ptn3460_bridge *ptn_bridge)
 102 {
 103         int ret;
 104         char val;
 105
 106         /* Load the selected edid into SRAM (accessed at PTN3460_EDID_ADDR) */
 107         ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_SRAM_LOAD_ADDR,
 108                         ptn_bridge->edid_emulation);
 109         if (ret) {
 110                 DRM_ERROR("Failed to transfer EDID to sram, ret=%d\n", ret);
 111                 return ret;
 112         }
 113
 114         /* Enable EDID emulation and select the desired EDID */
 115         val = 1 << PTN3460_EDID_ENABLE_EMULATION |
 116                 ptn_bridge->edid_emulation << PTN3460_EDID_EMULATION_SELECTION;
 117
 118         ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_EMULATION_ADDR, val);
 119         if (ret) {
 120                 DRM_ERROR("Failed to write EDID value, ret=%d\n", ret);
 121                 return ret;
 122         }
 123
 124         return 0;
 125 }
 126
 127 static void ptn3460_pre_enable(struct drm_bridge *bridge)
 128 {
 129         struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
 130         int ret;
 131
 132         if (ptn_bridge->enabled)
 133                 return;
 134
 135         gpiod_set_value(ptn_bridge->gpio_pd_n, 1);
 136
 137         gpiod_set_value(ptn_bridge->gpio_rst_n, 0);
 138         usleep_range(10, 20);
 139         gpiod_set_value(ptn_bridge->gpio_rst_n, 1);
 140
 141         if (drm_panel_prepare(ptn_bridge->panel)) {
 142                 DRM_ERROR("failed to prepare panel\n");
 143                 return;
 144         }
 145
 146         /*
 147          * There's a bug in the PTN chip where it falsely asserts hotplug before
 148          * it is fully functional. We're forced to wait for the maximum start up
 149          * time specified in the chip's datasheet to make sure we're really up.
 150          */
 151         msleep(90);
 152
 153         ret = ptn3460_select_edid(ptn_bridge);
 154         if (ret)
 155                 DRM_ERROR("Select EDID failed ret=%d\n", ret);
 156
 157         ptn_bridge->enabled = true;
 158 }
 159
 160 static void ptn3460_enable(struct drm_bridge *bridge)
 161 {
 162         struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
 163
 164         if (drm_panel_enable(ptn_bridge->panel)) {
 165                 DRM_ERROR("failed to enable panel\n");
 166                 return;
 167         }
 168 }
 169
 170 static void ptn3460_disable(struct drm_bridge *bridge)
 171 {
 172         struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
 173
 174         if (!ptn_bridge->enabled)
 175                 return;
 176
 177         ptn_bridge->enabled = false;
 178
 179         if (drm_panel_disable(ptn_bridge->panel)) {
 180                 DRM_ERROR("failed to disable panel\n");
 181                 return;
 182         }
 183
 184         gpiod_set_value(ptn_bridge->gpio_rst_n, 1);
 185         gpiod_set_value(ptn_bridge->gpio_pd_n, 0);
 186 }
 187
 188 static void ptn3460_post_disable(struct drm_bridge *bridge)
 189 {
 190         struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
 191
 192         if (drm_panel_unprepare(ptn_bridge->panel)) {
 193                 DRM_ERROR("failed to unprepare panel\n");
 194                 return;
 195         }
 196 }
 197
 198 static int ptn3460_get_modes(struct drm_connector *connector)
 199 {
 200         struct ptn3460_bridge *ptn_bridge;
 201         u8 *edid;
 202         int ret, num_modes = 0;
 203         bool power_off;
 204
 205         ptn_bridge = connector_to_ptn3460(connector);
 206
 207         if (ptn_bridge->edid)
 208                 return drm_add_edid_modes(connector, ptn_bridge->edid);
 209
 210         power_off = !ptn_bridge->enabled;
 211         ptn3460_pre_enable(&ptn_bridge->bridge);
 212
 213         edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
 214         if (!edid) {
 215                 DRM_ERROR("Failed to allocate EDID\n");
 216                 return 0;
 217         }
 218
 219         ret = ptn3460_read_bytes(ptn_bridge, PTN3460_EDID_ADDR, edid,
 220                         EDID_LENGTH);
 221         if (ret) {
 222                 kfree(edid);
 223                 goto out;
 224         }
 225
 226         ptn_bridge->edid = (struct edid *)edid;
 227         drm_mode_connector_update_edid_property(connector, ptn_bridge->edid);
 228
 229         num_modes = drm_add_edid_modes(connector, ptn_bridge->edid);
 230
 231 out:
 232         if (power_off)
 233                 ptn3460_disable(&ptn_bridge->bridge);
 234
 235         return num_modes;
 236 }
 237
 238 static struct drm_encoder *ptn3460_best_encoder(struct drm_connector *connector)
 239 {
 240         struct ptn3460_bridge *ptn_bridge = connector_to_ptn3460(connector);
 241
 242         return ptn_bridge->bridge.encoder;
 243 }
 244
 245 static struct drm_connector_helper_funcs ptn3460_connector_helper_funcs = {
 246         .get_modes = ptn3460_get_modes,
 247         .best_encoder = ptn3460_best_encoder,
 248 };
 249
 250 static enum drm_connector_status ptn3460_detect(struct drm_connector *connector,
 251                 bool force)
 252 {
 253         return connector_status_connected;
 254 }
 255
 256 static void ptn3460_connector_destroy(struct drm_connector *connector)
 257 {
 258         drm_connector_cleanup(connector);
 259 }
 260
 261 static struct drm_connector_funcs ptn3460_connector_funcs = {
 262         .dpms = drm_helper_connector_dpms,
 263         .fill_modes = drm_helper_probe_single_connector_modes,
 264         .detect = ptn3460_detect,
 265         .destroy = ptn3460_connector_destroy,
 266 };
 267
 268 static int ptn3460_bridge_attach(struct drm_bridge *bridge)
 269 {
 270         struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
 271         int ret;
 272
 273         if (!bridge->encoder) {
 274                 DRM_ERROR("Parent encoder object not found");
 275                 return -ENODEV;
 276         }
 277
 278         ptn_bridge->connector.polled = DRM_CONNECTOR_POLL_HPD;
 279         ret = drm_connector_init(bridge->dev, &ptn_bridge->connector,
 280                         &ptn3460_connector_funcs, DRM_MODE_CONNECTOR_LVDS);
 281         if (ret) {
 282                 DRM_ERROR("Failed to initialize connector with drm\n");
 283                 return ret;
 284         }
 285         drm_connector_helper_add(&ptn_bridge->connector,
 286                                         &ptn3460_connector_helper_funcs);
 287         drm_connector_register(&ptn_bridge->connector);
 288         drm_mode_connector_attach_encoder(&ptn_bridge->connector,
 289                                                         bridge->encoder);
 290
 291         if (ptn_bridge->panel)
 292                 drm_panel_attach(ptn_bridge->panel, &ptn_bridge->connector);
 293
 294         drm_helper_hpd_irq_event(ptn_bridge->connector.dev);
 295
 296         return ret;
 297 }
 298
 299 static struct drm_bridge_funcs ptn3460_bridge_funcs = {
 300         .pre_enable = ptn3460_pre_enable,
 301         .enable = ptn3460_enable,
 302         .disable = ptn3460_disable,
 303         .post_disable = ptn3460_post_disable,
 304         .attach = ptn3460_bridge_attach,
 305 };
 306
 307 static int ptn3460_probe(struct i2c_client *client,
 308                                 const struct i2c_device_id *id)
 309 {
 310         struct device *dev = &client->dev;
 311         struct ptn3460_bridge *ptn_bridge;
 312         struct device_node *endpoint, *panel_node;
 313         int ret;
 314
 315         ptn_bridge = devm_kzalloc(dev, sizeof(*ptn_bridge), GFP_KERNEL);
 316         if (!ptn_bridge) {
 317                 return -ENOMEM;
 318         }
 319
 320         endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);
 321         if (endpoint) {
 322                 panel_node = of_graph_get_remote_port_parent(endpoint);
 323                 if (panel_node) {
 324                         ptn_bridge->panel = of_drm_find_panel(panel_node);
 325                         of_node_put(panel_node);
 326                         if (!ptn_bridge->panel)
 327                                 return -EPROBE_DEFER;
 328                 }
 329         }
 330
 331         ptn_bridge->client = client;
 332
 333         ptn_bridge->gpio_pd_n = devm_gpiod_get(&client->dev, "powerdown");
 334         if (IS_ERR(ptn_bridge->gpio_pd_n)) {
 335                 ret = PTR_ERR(ptn_bridge->gpio_pd_n);
 336                 dev_err(dev, "cannot get gpio_pd_n %d\n", ret);
 337                 return ret;
 338         }
 339
 340         ret = gpiod_direction_output(ptn_bridge->gpio_pd_n, 1);
 341         if (ret) {
 342                 DRM_ERROR("cannot configure gpio_pd_n\n");
 343                 return ret;
 344         }
 345
 346         ptn_bridge->gpio_rst_n = devm_gpiod_get(&client->dev, "reset");
 347         if (IS_ERR(ptn_bridge->gpio_rst_n)) {
 348                 ret = PTR_ERR(ptn_bridge->gpio_rst_n);
 349                 DRM_ERROR("cannot get gpio_rst_n %d\n", ret);
 350                 return ret;
 351         }
 352         /*
 353          * Request the reset pin low to avoid the bridge being
 354          * initialized prematurely
 355          */
 356         ret = gpiod_direction_output(ptn_bridge->gpio_rst_n, 0);
 357         if (ret) {
 358                 DRM_ERROR("cannot configure gpio_rst_n\n");
 359                 return ret;
 360         }
 361
 362         ret = of_property_read_u32(dev->of_node, "edid-emulation",
 363                         &ptn_bridge->edid_emulation);
 364         if (ret) {
 365                 dev_err(dev, "Can't read EDID emulation value\n");
 366                 return ret;
 367         }
 368
 369         ptn_bridge->bridge.funcs = &ptn3460_bridge_funcs;
 370         ptn_bridge->bridge.of_node = dev->of_node;
 371         ret = drm_bridge_add(&ptn_bridge->bridge);
 372         if (ret) {
 373                 DRM_ERROR("Failed to add bridge\n");
 374                 return ret;
 375         }
 376
 377         i2c_set_clientdata(client, ptn_bridge);
 378
 379         return 0;
 380 }
 381
 382 static int ptn3460_remove(struct i2c_client *client)
 383 {
 384         struct ptn3460_bridge *ptn_bridge = i2c_get_clientdata(client);
 385
 386         drm_bridge_remove(&ptn_bridge->bridge);
 387
 388         return 0;
 389 }
 390
 391 static const struct i2c_device_id ptn3460_i2c_table[] = {
 392         {"nxp,ptn3460", 0},
 393         {},
 394 };
 395 MODULE_DEVICE_TABLE(i2c, ptn3460_i2c_table);
 396
 397 static const struct of_device_id ptn3460_match[] = {
 398         { .compatible = "nxp,ptn3460" },
 399         {},
 400 };
 401 MODULE_DEVICE_TABLE(of, ptn3460_match);
 402
 403 static struct i2c_driver ptn3460_driver = {
 404         .id_table       = ptn3460_i2c_table,
 405         .probe          = ptn3460_probe,
 406         .remove         = ptn3460_remove,
 407         .driver         = {
 408                 .name   = "nxp,ptn3460",
 409                 .owner  = THIS_MODULE,
 410                 .of_match_table = ptn3460_match,
 411         },
 412 };
 413 module_i2c_driver(ptn3460_driver);
 414
 415 MODULE_AUTHOR("Sean Paul <seanpaul@chromium.org>");
 416 MODULE_DESCRIPTION("NXP ptn3460 eDP-LVDS converter driver");
 417 MODULE_LICENSE("GPL v2");